Q: A little oil in radiator?

Since you have a manual transmission, there are no transmission oils going into a cooler in the radiator. The only way coolant and oil can mix is from the engine oil getting into the coolant passing in the engine. This can happen due to a leaking head gasket, or corrosion in the head or block eating through the gasket or metal part.

A pressure test on the radiator may point out the leak in the head or block. If it does not, then the leak is internal and may require the engine to be disassembled and pressure tested. If you want to have this diagnosed by a professional, a certified technician from YourMechanic can come to your car’s location to inspect your system for oil leaks and advise you on a repair.